The present invention relates to water craft steering and more particularly to an apparatus and method for steering jet propelled water craft.
Jet propelled water craft are well known. In a typical jet propelled water craft, a jet propulsion unit is installed or incorporated into a stem portion of the hull, and a water tunnel in the bottom of the hull provides water to the jet propulsion unit. A drive shaft is mated with an impeller which is rotatably secured to a stator hub within a stator housing. Stator vanes secure the stator hub within the stator housing and redirect the swirling flow from the impellers into non-swirling flow. A water stream is driven from the exit housing to provide forward thrust to the water craft.
In a typical jet propelled water craft, steering is accomplished using a cone or nozzle that is pivotally secured to the exit nozzle. If forward thrust is being providing and the operator wishes to turn to the right or starboard, the steering nozzle is pivoted to the right or starboard. This provides a thrust component at the stern of the boat in the left or port direction which in turn drives the bow of the boat to the right or starboard side. Similarly, to turn to the left or port side, the nozzle is rotated to the left or port side. This method of steering works reasonably well but suffers from some disadvantages. For example, the range of motion of a typical steering nozzle or cone is only approximately 30xc2x0 in either direction. This places undesirable limits on the left and right thrust component of the water stream, thereby placing undesirable limits on the magnitude of the left and right thrust available. Further, because the nozzle redirects the entire water stream to accomplish a turn, this method of steering makes inefficient use of the water stream provided by the jet propulsion unit and undesirably reduces the forward thrust of the stream during turning.
In a typical jet propelled water craft, reverse thrust is provided using a reverse nozzle that is pivotally attached to the steering nozzle and that pivots up or down to block the exit of the steering nozzle and redirect the water stream downward and forward. This provides reverse thrust. If the steering nozzle is turned while the reverse nozzle redirects the flow of the water stream, a portion of the redirected water stream provides lateral thrust to aid in steering while in reverse. Again, because the steering and reverse nozzles redirect the entire water stream to accomplish a turn in reverse, this method makes inefficient use of the water stream provided by the jet propulsion unit. Also, the lateral thrust available while in reverse is typically very limited. Redirecting the entire water stream to accomplish a turn while in reverse also reduces the rearward thrust of the stream during turning.
It is therefore an object of the present invention to provide an apparatus and method for steering a jet propelled water craft that allows for improved handling in forward and reverse.
It is a further object of the present invention to provide an apparatus and method of the above type that diverts a portion of a water stream to provide lateral thrust.
It is a still further object of the present invention to provide an apparatus and method of the above type that provides for increased forward or rearward thrust during turning.
It is a still further object of the present invention to provide an apparatus and method of the above type that provides for increased lateral thrust during turning.
It is a still further object of the present invention to provide an apparatus and method of the above type that makes efficient use of a water stream provided by a jet propulsion unit.
It is a still further object of the present invention to provide an apparatus and method of the above type that avoids unnecessary diversion of a water stream provided by a jet propulsion unit.
It is a still further object of the present invention to provide an apparatus and method of the above type that avoids the power demands required to divert an entire water stream provided by a jet propulsion unit.
It is a still further object of the present invention to provide an apparatus and method of the above type that provides added flexibility in providing thrust at greater angles from a centerline of a water craft.
It is a still further object of the present invention to provide an apparatus and method of the above type that provides lateral thrust at angles greater than 30xc2x0 from a centerline of a water craft.
It is a still further object of the present invention to provide an apparatus and method of the above type that provides lateral thrust at an angle of approximately 70xc2x0 from a centerline of a water craft.
It is a still further object of the present invention to provide an apparatus and method of the above type that provides for neutral operation in which a water stream from a jet propulsion unit is diverted to provided neither forward nor reverse thrust.
It is a still further object of the present invention to provide an apparatus and method of the above type that provides for simple linear movement of side and reverse diverters.
It is a still further object of the present invention to provide an apparatus and method of the above type that may be used in connection with water craft having multiple jet propulsion units.
It is a still further object of the present invention to provide an apparatus and method of the above type in which a frame of simple construction houses both side and reverse diverters.
It is a still further object of the present invention to provide an apparatus and method of the above type that provides for improved handling while minimizing any unnecessary disruption of a water stream from a jet propulsion unit.
It is a still further object of the present invention to provide an apparatus and method of the above type that provides for improved control of reverse thrust.
It is a still further object of the present invention to provide an apparatus and method of the above type that uses two reverse diverters for improved control of reverse thrust.
It is a still further object of the present invention to provide an apparatus and method of the above type that uses non-linear motion to move diverters into and out of the path of a water stream.
It is a still further object of the present invention to provide an apparatus and method of the above type that uses a frame that is pivotal about two axes to move diverters into and out of the path of a water stream.
It is a still further object of the present invention to provide an apparatus and method of the above type that moves a frame from a position parallel to a jet propulsion discharge outlet during un-diverted flow to a position that is not parallel to a jet propulsion discharge outlet during diverted flow.
Toward the fulfillment of these and other objects and advantages, the apparatus and method of the present invention allow a water stream to be divided so that a portion continues to provide forward or reverse thrust that is substantially parallel to a centerline of a water craft while a portion is diverted to provide lateral thrust that is not substantially parallel to a centerline of a water craft. The apparatus of the present invention has a frame and a side diverter operably connected to the frame, the side diverter being movable into and out of the path of a water stream from a jet propulsion unit to divert at least a portion of the water stream to provide lateral thrust. The apparatus preferably has two side diverters that may or may not be independently operable. The apparatus also preferably has one or more reverse diverters operably connected to the frame. The frame is preferably pivoted about two axes to move the side diverters into and out of the path of the water stream, and the reverse diverter preferably pivots about an axis that is perpendicular to these axes.